Nonluminous pyrotechnic mixture for a projectile



NONLUIWINOUS PYROTECHNIC MIXTURE FOR A PROJECTILE Raymond H. Heiskell, Compton, Calif.

No Drawing. Application June 29, 1948, Serial No. 35,961

3 Claims. (Ci. 52-2) (Granted under Title 35, U. S. Code (1952), see. 266) This invention relates to a non-luminous pyrotechnic mixture for use in a projectile and more particularly to a mixture especially adapted to ignite the burster charge arranged within the projectile while the projectile is in flight in the event that the aircraft target is missed.

Heretofore pyrotechnic compositions used in the tracer cavity of a projectile for igniting the burster charge and exploding the projectile while in flight, should the projectile miss an aircraft target, have not been altogether satisfactory especially when used in night encounters, in that under condition of darkness the flash therefrom upon ignition of the pyrotechnic mixture by the igniter mixture caused excessive light flash at the muzzle of the gun, thus illuminating and disclosing the position of the gun to the enemy. Furthermore such compositions were sufliciently luminous to enable the trajectory of the projectile to be visible particularly at night. Such compositions also proved not altogether satisfactory inasmuch as the burning rate thereof was too rapid for the purpose intended and the ignition sensitivity characteristic thereof was noni:

uniform.

The present invention is especially adapted to obviate the above mentioned light flash occurring at the gun muzzle and during the flight of the projectile and to provide a mixture in which the burning and sensitivity characteristics thereof have been greatly improved.

An object of this invention is to provide a new and improved non-luminous mixture for use in a projectile m which the trajectory thereof will not be visible and in which ignition of the burster charge within the projectile is initiated while the projectile is in flight and when a predetermined period of time has elapsed after the projectile has been fired from the gun, should the projectile miss the aircraft target.

Other objects and advantages of the present invention will become apparent during the course of the following description taken in connection with the following claims.

in accordance with the present invention the newand improved non-luminous mixture for initiating the igmtion of the burster charge arranged within the projectile is composed of barium peroxide, antimony sulnde, asphaltum, and graphite.

A non-luminous pyrotechnic mixture capable of functioning in the manner herein described consists of a peroxide of an alkaline earth metal such, for example as barium peroxide 60-70.7%, a substance of crystalline structure such, for example, as antimony sulfide 21.3- 35%, a bitumen substance such, for example, as asphaltum 14% a friction reducing carbon such, for example, as graphite 14%. The proportions of asphaltum may be varied to increase or decrease the burning rate of the mixture, if desired, and frictional sensitivity of the mixture may be modified by increasing or decreasing the amount of graphite therein.

A particular example of a pyrotechnic mixture possessing all of the desired features and which is invisible when burning is as follows:

ice

Ingredients Mesh Size Percentage Barium Peroxide 50 6O Antimony Sulfide 50 35 A snhaltum 50 4 Granhitn 50 1 In preparing the ingredients comprising the non-luminous pyrotechnic mixture it has been found that the most satisfactory results are obtained when the ingredients thereof are of such proportions as to pass through a U. S. standard sieve, mesh size 50, prior to the mixing together of the ingredients. When sifting of the ingredients has been completed the ingredients are then thoroughly mixed in any suitable manner but preferably by placing the ingredients in a mixing churn with a suitable number of rubber balls, the churn being of any type suitable for the purpose such, for example, as the type known in the art as the Abbe mixer churn. The time period required to mix the ingredients thoroughly when the churn is set in operation is approximately 30 minutes. After the ingredients have been thoroughly mixed in the aforesaid manner the mixture is pressed into pellets at a pressure of approximately 25,000 p. s. i.

The asphaltum is added to the mixture to decrease the burning rate thereof and to stabilize the combustible characteristics of the mixture such that the mixture is suificiently sensitive to be readily ignited and to burn slowly until entirely consumed. In preparing the nonluminous mixture it has been found that when the barium peroxide, antimony sulfide, and asphaltum was mixed with the graphite in the aforesaid proportions the frictional sensitivity of the particles of which the non-luminous is composed is sufficiently low to prevent premature detonation of the mixture during pressing and loading the mixture in the cavity of the projectile.

In loading the non-luminous mixture in pellet form into the tracer cavity of the projectile it has been found that the best result was obtained when 1 gram of starter mixture composed of barium peroxide, magnesium and charcoal and 1 gram of loose igniter composition was pressed into the cavity together with the aforesaid pellets at a pressure 90,000 p. s. i. It will be understood that any suitable igniter composition may be used for igniting the non-luminous mixture of the present invention such, for example, as the type disclosed and claimed in my copending application for Composition for Tracer Unit, Serial Number 35,960, filed June 29, 1948.

From the foregoing description it will be understood that a non-luminous mixture for a projectile has been compounded and constructed in which the trajectory of the projectile will not be visible and in which ignition of the burster charge of the projectile is initiated by the nonluminous mixture a predetermined period of time after ignition of the igniter composition and while the projectile is in flight, should the projectile miss the aircraft target.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that the scope of the appended claims of the invention may be practiced otherwise than as specifically described.

The invention herein described and claimed may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A non-luminous mixture for initiating ignition of the burster charge of a projectile comprising barium peroxide 60%, antimony sulfide 35%, asphaltum 4%, graphite 1%.

2. A non-luminous igniter for initiating ignition of the burster charge of a projectile comprising-a peroxide of an 2,714,061 v i 3 4 alkaline earth metal 60% to 70.7%, antimony sulfide References Cited in the file of this patent 21.3% to 35%, a bitumen-mineral substance 1-4%,-and

U E TA 'TE a friction reducing substance. NIT D S TES PA NTS 3. A non-luminous igniter for initiating ignition of the 19301653 1933 burster charge of a' projectile comprising barium'peroxide 2,410,801 Audneth 1946 60% to*70.7%,- antimony sulfide 2 13% m 35%, asphal- 2,416,639

Pearsall Feb. 25, 1947 tum-1-4%, andfrom 1%" to'4% of graphite. 

2. A NON-LUMINOUS IGNITER FOR INITATING IGNATION OF THE BURSTER CHARGE OF A PROJECTILE COMPRISING IGNITION OF THE ALKALINE EARTH METAL 60% TO 70.7%, ANTIMONY SULFIDE 21.3% TO 35%, A BITUMEN MINERAL SUBSTANCE 1-4%, AND A FRICTION REDUCING SUBSTANCE. 